I am trying to construct a time series of NDVI derived from Landsat 5, 7 and 8 using the Google Earth Engine's Python API. To ensure the validity of this TS, I am harmonising the TM/ETM+ imagery to OLI using the coefficients found by Roy et al. (2016, https://doi.org/10.1016/j.rse.2015.12.024), following the method outlined on https://developers.google.com/earth-engine/tutorials/community/landsat-etm-to-oli-harmonization. As the NDVI TS is pretty central to my research question, I would like to quantitatively assess the performance of this harmonisation using the OLS regression approach used by Roy et al. However, this requires overlapping pixels from different paths at similar dates to be extracted.
Is there a way of extracting this in GEE?